Question

Have you ever noticed the fact that two siblings can have different personalities? Even though two people may be members of the same family, it does mean that they will behave in similar ways.
The same things can be said about elements in a group ("family") on the periodic table. For example, fluorine and iodine are members of the halogen family, but their physical properties are different, as shown in the table below.

Element	Melting Point ${(}^{\circ }C)$	Boiling Point ${(}^{\circ }C)$
Fluorine	$-220$	$-188$
Iodine	$+118$	$+184$

What of the following is the BEST explanation for these differences in melting and boiling point?

• A. Fluorine has a higher value for electronegativity than iodine.
• B. The covalent bond in the fluorine molecule is stronger than the covalent bond in the iodine molecule.
• C. Iodine molecules are larger and more polarizable than fluorine molecules.
• D. Fluorine is a nonpolar molecule, but iodine is a polar molecule.

Answer 1

Answer: (A), (C)

The correct options are
A Fluorine has a higher value for electronegativity than iodine.
C Iodine molecules are larger and more polarizable than fluorine molecules.

Fluorine is more electronegative than iodine because the atom size of F is less than I so the tendency to attract electron increases

Iodine is more polarizable than fluorine (this is true for both the individual elements and the diatomic molecules).